1. Field Of The Invention
This invention relates to universal joints, and more particularly, to a universal joint having intermeshing teeth on curved surfaces and adapted for attachment to a socket wrench or similar device.
2. Description Of The Prior Art
Universal joints are well known in the art, but most are complex and not easily adapted for use with such devices as socket wrenches. Universal joints typically are quite limited in the angle at which the two shafts connected thereto can be angularly displaced.
One universal joint which allows a fairly significant angular displacement between the two shafts is disclosed in U. S. Pat. No. 912,096 to Elkan. This apparatus includes two cylinder-like gear members having teeth on their inner ends and sides so that they may mesh with each other whether in or out of axial alignment. The gear members are connected to one another by a pair of pivotally connected links having collars on their outer ends. The collars are positioned in cavities within the gear members, and springs are used to bias the collars such that the gear members are maintained in meshing engagement. When the gears are angularly displaced, the links are free to slide axially within the gear members and pivot as necessary. One problem with such an arrangement is that the angular displacement of the gears may only occur in the plane in which the links are pivoted, unlike the present invention in which the elements may be pivoted in any direction at any time. Another problem is that upon rotation of the two shafts when in angular displacement, the links remain basically stationary. This requires that the springs must rotate on an inner shoulder within the gear members. This can cause undesirable friction and binding.
In a case where the shafts are to be parallel, an alternate embodiment of Elkan shows the inner ends of the links connected by a cable or other flexible connecting link. However, it is possible that this would not work properly, because the springs would cause the links to rotate with the shafts which in turn would cause the flexible cable to twist around the ends of the links in an undesirable manner.
The apparatus of the present invention solves these problems by eliminating the links and providing a flexible connection between spring biased plates. Thus, the binding problem of Elkan is eliminated. Further, the substantially curved gears of the present invention provide a much smoother angular displacement and transmission of rotating force than would be possible with Elkan.
The gearing device of Schulze-Berge, in U. S. Pat. No. 305,714, shows spherical and hemispherical gear members which are intermeshed. However, these gears are interconnected by a complex system of external links. The present invention which uses a simple flexible connector eliminates all of the problems and complexity of Shulze-Berge.